linux/Documentation/devicetree/bindings/mmc/mmc-card.txt
Hans de Goede 81f8a7be66 mmc: Add support for marking hpi as broken through devicetree
The eMMC on a tablet I've will stop working / communicating as soon as
the kernel executes:

		mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				EXT_CSD_HPI_MGMT, 1,
 				card->ext_csd.generic_cmd6_time);

There seems to be no way to reliable identify eMMC-s which have a broken
hpi implementation, but at least for eMMC's which are soldered onto a board
we can work around this by specifying that hpi is broken in devicetree.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2015-04-02 10:59:10 +02:00

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mmc-card / eMMC bindings
------------------------
This documents describes the devicetree bindings for a mmc-host controller
child node describing a mmc-card / an eMMC, see "Use of Function subnodes"
in mmc.txt
Required properties:
-compatible : Must be "mmc-card"
-reg : Must be <0>
Optional properties:
-broken-hpi : Use this to indicate that the mmc-card has a broken hpi
implementation, and that hpi should not be used
Example:
&mmc2 {
pinctrl-names = "default";
pinctrl-0 = <&mmc2_pins_a>;
vmmc-supply = <&reg_vcc3v3>;
bus-width = <8>;
non-removable;
status = "okay";
mmccard: mmccard@0 {
reg = <0>;
compatible = "mmc-card";
broken-hpi;
};
};